1. Field of the Invention
The invention relates to an apparatus for the fractional distillation of hydrocarbons or other organic compounds, and is specifically directed to a single vessel apparatus in which fractional distillation is performed to produce more than two high purity product streams, and which contains two rectification zones and two stripping zones.
2. Description of the Prior Art
There is a large body of knowledge in the field of fractionation, wherein the uniformly used method to produce three separate high purity fractions employs two distinct vessels, such as two columns, connected to separate out one fraction from the mixture in a first column, and to separate the other two fractions in the second column. The apparatus of the present invention uses only one vessel, but has more than one rectification and stripping section located within this vessel. In the prior art, a separate external reflux system is located at the top of each rectification section and each column rests on a separate foundation. The prior art also includes stacking two fractionation units within the same vessel to reduce capital costs. The present invention is distinguished by the open communication between the units, and by the telescopic insertion of the two columns to form an annular stripping section between the stabbed in top portion of the lower fractionation unit and the bottom portion of the top fractionation unit.